2. De experimento probandi spiritum vini Gallici, per quam usitato, sed revera falso et fallaci.
Some merchants in Holland, England, Hamburg, and Dantzic, were in possession of what they considered an infallible test to distinguish French brandy from every other kind of spirit. It was a dusky yellowish liquid. When one or two drops of it were let fall into a glass of French brandy, a beautiful blue colour appeared at the bottom of the glass, and when the brandy is stirred, the whole liquid becomes azure. But if the spirit tried be malt spirit, no such colour appears in the glass. Neumann ascertained that the test liquid was merely a solution of sulphate of iron in water, and that the blue colour was the consequence of the brandy having been kept in oak casks, and thus having dissolved a portion of tannin. Every spirit will exhibit the same colour, if it has been kept in oak casks.
3. De salibus alkalino-fixis.
4. De camphora thymi.
5. De ambragrysea.
His other papers, published in Germany, are the following:
In the Ephemerides.
1. De oleo distillato formicorum æthereo.
2. De albumine ovi succino simili.